Evolution getting faster by the millennium

By Richard Macey

NATURE'S race to create the perfect person has shifted into top gear, with humans evolving 100 times faster than at any time since the rise of man some 6 million years ago.

That is the finding of researchers who have sifted through data collected by the international effort to map our genetic blueprint.

The pace of human evolution in the past 5000 years was "immense … something nobody expected", John Hawks, a University of Wisconsin-Madison anthropologist, said yesterday.

Advertisement

His team found evidence that 1800 genes, or 7 per cent of all those in the human body, had undergone natural selection in the past 5000 years. "We are more different genetically from people living 5000 years ago than they were from Neanderthals," said Professor Hawks. "In the last 40,000 years humans have changed as much as they did in the previous 2 million years.

"Five thousand years ago Europeans and Asians would have been darker skinned. Almost nobody had blue eyes. No one was resistant to malaria. No adults were drinking milk."

A key to the ever increasing pace of human evolution was the world's population, which had boomed from a few million 10,000 years ago, to more than 6.5 billion today, dramatically expanding mankind's DNA pool.

"Every person has a very slight chance of having a good mutation," said Dr Hawks. "When you get more and more people you are rolling the genetic dice more often."

Another driver of natural selection was disease. Those without resistance often died before handing on their genes.

A genetic change that allowed northern European adults to digest milk was directly tied to the rise of farming.

Dr Hawks said the value of most genetic changes, including many in the brain, remained a mystery. Some could involve personality, or help our brains be "more perceptive".

Dr Hawks predicted human evolution would race along for a few more generations. "New diseases come along. We are always trying to outrun disease. I hope we never have another malaria, but if we do there there will be a few people who are resistant."

He tipped evolution's next course change could make humans more fertile. "Natural selection cares about how many children you have. People will have kids younger and younger.

If we are the survivors of malaria, the survivors of tomorrow will be the children of those who had kids young."

Dr Hawks suspected natural selection would one day be bypassed altogether by genetic manipulation technology.

"Genetic engineering will make all this irrelevant. If people want green-haired kids they will go to the doctor and get them in 100 years."